Punch and die mechanism



July 1, 1947. FEITL I 2,423,423

PUNCH AND DIE MECHANISM Filed NOV. 50, 1945 v 2 Sheets-Sheet 1 July 1, 1947. FElTL PUNCH AND DIE MECHANISM Filed Nov. 30, 1945 2 Sheets-Sheet 2 Patented July 1, 1947 PUNCH AND ms MECHANISM Rudolf Feitl, Brooklyn, N. Y., assignor to Waldes Koh-I-Noor, Inc., Long Island City, N. Y., a corporation of New York Application November 30, 1945, Serial No. 631,996

Claims. 1

This invention relates to a punch and die mechanism for notching the side edges of strip material, either metal or plastic, and while not limited thereto, will be described in its application to the manufacture of slide fastener elements.

-As is well known, slide fastener elements of the type with which the present invention is concerned are conventionally formed with an interlocking head portion provided with a projection extending from one face thereof and with a complemental recess in its other face which is adapted to receive the locking projection of an adjacent element, and with a pair of legs adapted to form clamping jaws by which the elements are attached to the beaded edge of a flexible stringer or tape.

According to a known method of manufacture, such slide fastener elements are blanked from a flat strip of metal or plastic stock having substantially the same width as that of the elements with their legs (clamping jaws) spread and in such manner that the head portion of one blank nests in the space between the spread legs of the next following element. By such method, the strip stockis intermittently fed to a punch and die mechanism which in each dwell period of the strip, operates to form the head locking means, i. e. the projection on one side and the recess on the other side of a head forming portion of the strip, as well as to contour a blank by notching the strip along its side edges as by severing triangular pieces of stock therefrom, and by blanking out the head and leg portions of an element. The following feed motions of the strip advance the element blanks as they are successively so formed and disposed in their longitudinally nested relation to a transversely advancing tape, whereupon the clamping legs of the most advanced element presented to the tape are clamped over the beaded edge thereof.

The present invention relates to the punch.

and die mechcanism by which the strip is suitably contoured along it side edges and the elements blanked as aforesaid, a principal object being to provide a punch and die mechanism for notching the strip along its edges which incorporates edgenotching dies of a type that can be readily manufactured, are simple to re-shape, and have exceedingly long life. In prior edge-contouring dies, the sharp edges of the' die were quickly dulled and required frequent regrinding. The regrinding of die parts employed in the manufacture of slide fastener elements is a somewhat difflcult operation requiring careful attention and somewhat complex tools. This difficulty is over come by the present invention through the provision of a sectional die, the edge contouring parts of which are of simple shape and therefore easy to manufacture and re-shape, and are moreover so formed that they are interchangeable and invertible as well, with the result that their life is increased four-fold as compared with known dies or parts thereof of similar function.

An equally important object of the invention is to provide in a punch and die mechanism the necessary means for assuring absolute correct positioning of the effective parts of the die mechanism relative to the center line thereof. The fulfillment of this requirement is especially important in a sectionally constructed die because the die sections must be maintained in exact position relative to each other, to the mechanism center line, and to the corresponding parts of the punch. Moreover, when the small size of slide fastener elements is considered, taken with the fact that a large number of such elements arranged in chain formation on a fastener tape or stringer must be so related as to interlock with the corresponding elements similarly arranged on the opposite tape or stringer, it will be appreciated that accurate shape and symmetry of the fastener elements is imperative for the smooth functioning of the fastener. A punch and die mechanism according to the present invention satisfies these requirements by insuring that the cutting parts of the die mechanism are correctly centered and in perfect alignment.

The aforesaid objects are achieved according to this invention through the provision of a sectional die, i. e. a die composed of sections of simple shape which are so formed that they can be and are in fact rigidly held against locating surfaces provided within the die body in such manner that they maintain an exact symmetric and invariable position relative to the center line of the die mechanism. More particularly, the invention provides a die composed of sectional die parts for matching the edges of a strip being fed thereto, which are provided with relatively inclined surfaces secured against complemental wedge-like surfaces of another die part which is invariably and securely located in the fixed die body, and with curved surfaces engaging against complementally curved surfaces provided directly in the die body. Similarly, the punchis held in proper position by wedge-like parts engaging against inclined surfaces of the punch and which can be tightened by screws or similar means in the direction of the center line of the punch body, Q the end. that the punch also i always maining center line of the mechanism and to the corresponding die parts.

These and other features and advantages will be apparent from the following analysis of the invention, taken in connection with the accompanying drawings, in which- Fig. 1 is a perspective view of a complete punch and die mechanism according to the invention;

Fig. 2 is a top plan view of the die portion of the mechanism as illustrated in Fig. 1;

Fig. 3 is a plan view of a piece of strip stock with elements blanked therefrom shown in their nested relation in which they are presented to the fastener tape;

Fig. 4 is an exploded view in perspective illustrating the individual parts making up a die according to the invention; and

Fig. 5 is a similar exploded perspective view illustrating the several parts making up the punch.

Referring to the drawings, reference character I (Figs. 1 and 3) designates a strip of material from which elements such as slide fastener elements are to be blanked, it being assumed that the strip in Fig. 1 is advancing endwise and to the right in a guideway 2 provided in the die center block 3, shown in detail in Fig. 4. The center block is flanked by side die blocks 4 and 5 (Figs. 1 and 4) fixedly seated in the die bolster parts 6 and 6a, the side blocks being spaced to provide a longitudinal slot in which the center block 3 is fitted.

As seen in Fig. 3, the formed element blanks each comprises a. head portion 1 from which the legs 8, 8a extend divergently, the legs being separated by a recess 9 which is filled by the head portion 1 of the next advance element. As hereinbefore indicated, the element head portions 1 are each formed with a locking projection Ill extending from one face thereof and with a corresponding recess (no-t shown) in its opposite face. The head projection and its corresponding recess are coined by the die part I I (Figs. 1 and 4) and a corresponding punch part 36 (Fig. 5) to be referred to hereinafter, said die part I I having a recess-forming pin [2 extending from its upper face and being contained in the slot l3 of a U- shaped die part l4 best shown in Fig. 4. As seen in Figs, 1 and 2, the die part l4 and its contained die part II are held in the slot between the side blocks 4 and 5 and forwardly of the center block 3 against which it engages.

In the contouring of the blanks substantially triangular pieces are severed from the opposite edges of the strip. This results in the strip having interrupted edge portions l5, l5a, which are formed by the edges of the strip itself, and intermediate symmetrically disposed notches defined by the concave edges I6, Mia, and by straight edges l1, Ha. These notch-forming edges, which particularly determine the shape or contour of the element clamping jaws, are cut by the edges of the two vertically arranged die parts or inserts l8, Ilia of semi-circular cross section as best seen in Fig. 4. It will be observed from a comparison of Figs. 2 and 3 that the arcuate cutting edges l9, Illa of the die parts I8, I80 correspond to the concave notch edges l5, |6a and that the straight.

edge portions 20, a of the die parts correspond with the straight notch edges l1, Ila.

To punch out the rounded head edges of the elements and at the same time to sever the most advanced element blank from the strip, a separate die part 22, having a semi-circular top cutting edge 23 (Fig. 4) is provided. The die part 22 seats blocks are use for cutting purposes.

4 in a recess provided therefor in the front faces of the side blocksv 4, 5, as seen in Figs. 1 and 2. It will be understood that the cutting of the outer and inner curved edges of the head portion of the elements, (as defined by the line of cut 2|.) the edge notching as generally described, and the shearing off of the most advanced blank, are

effected by one and the same stroke of the punch to be described.

To insure a perfectly secure and correct positioning of the semi-circular die parts I8, I 8a with respect to the center line of the mechanism, the said die parts are in the first place so mounted that only a corner of each protrudes beyond the planes of the slot side walls, i. e. the adjacent vertical walls of the flanking side blocks 4, 5. The remaining, major cross sectional portions of said die parts l8, i8a seat in correspondingly shaped bores 24, 24a provided for their reception in the side blocks 4 and 5, and which open into the slot therebetween. As seen in Fig. 4, the bore walls are lengthened in arcuate direction so as to provide additional abutment surfaces for the said die parts, by the provision of protruding edges 2'4b, 240. To insure invariable angular position of the die parts I8, I80. their straight or diametrical faces engage against oppositely inclined wedgelike surfaces 25, 25a of a vertical tongue or projection 26 formed on the lower front end edge of the die part l4. By the described arrangement, the die parts l8, [8a, whose cutting edges form the critical notch forming edges I5, I! of the elements, are positively located and held in exactly centered position between the surfaces of the bores 24, 24a of the side blocks and the inclined wedge-like surfaces 25, 25a of the die part l4.

In assembly, the aforesaid die parts, which are supported on a horizontal base plate 28a, are arranged in their proper position within the slot between the side blocks 4, 5. Thereupon, front and rear end plates 21, 28 which are adapted to be secured as by bolts or screw to the rear and front faces of side blocks, are tightened with the result that all said die parts are secured in their proper and correctly centered position.

An important advantage of'this arrangement resides in the fact that the die parts or inserts l8, l8a are not only interchangeable with one another, but also, by the simple expedient of grinding both ends thereof, they can be inverted or turned up-side-down with the result that the life of said die parts is increased fourfold. This increased life follows from the fact that only the corners protruding into the slot between side Hence, by interchanging said die parts, the opposite corners can now be used after the previously used working edges have become dulled. By inverting the die parts, both of the opposite corners thereof may be used in turn, with the result that die parts as herein contemplated having a working life four. times that obtainable with conventional notching dies.

To provide for step-by-step advance of the strip and foremost element or elements, it is necessary that the strip be raised slightly so as to clear the pin l2 of the die part II. To this end, there is provided a knock-out member 29 illustrated in detail in Fig. 4, which has grooves in its side faces accommodating the protruding corners of the die parts l8, l8a, an is guided in an appropriately shaped recess 30 formed in the base plate 28a. The knock-out member 29 is actuated in timed relation to the feed motion of the strip to raise the 'metal strip and release it from the pin l2 of the die part II, whereupon the strip and formed elements can be advanced. At the same, time, the knock-out member 29 removes the scrap material resulting from the edge notching operation. It will be understood that during the period that the strip is lifted, the most advanced element is presented to the tape which moves transversely in a tape slot conventionally provided in the die bolster and forward die parts, and through the recess 9 between the carried by a reciprocating ram as is conventional,

punch part 3| is vertically arranged and is provided in its side faces with parallel recesses 32, 32a of approximate V-section as defined by inclined edges 33, 33a and 34, 3411 which correspond to and cooperate with the cutting edges I9, I91: and 20, 20a, respectively, of the semicircular die parts I8, I 8a. The front face of the punch is provided with a recess 35 having a cutting edge 35a which corresponds with the cutting edge 23 of the die part 22. For clarity the cutting edges of the punch have been indicated in Fig. 5 on the top thereof insteadof the bottom where they are eifective. The punch part 36, which cooperates with. the die part II, is mounted directly behind the punch 3|. Its bottom face is provided with a recess 36a which cooperates with the pin l2 of die pa rt I in coining the head projection and its underface recess.

The aforesaid individual parts of the punch assembly, and particularly the punch 3|, are secured in fixed position in the vertical slot of a mounting block 38 by two identically formed bolt-like members 36, 36a, provided at their ends with wedge-like heads 31, 31a which want with the inclined surfaces of the side face recesses 32, 32a of the punch, and effect wedging or keying thereof in its properly centralized position relative to the mounting block 38 and hence to the die center line. The bolt-like members extend through bores 38a, 38b formed in the mounting block 38 and are tightened by screw 40, 40a which are threaded into suitable threaded bores extending into the relatively rear end of the boltlike members. The screws 40, 40a pass through holes 4|, Ma provided therefor in an end plate 39 which engages against the rear face of block 38. Tightening of the bolt-like members 36, 3611 results in the wedge-like heads 31, 31a thereof having tight pressure lit in the side recesses of the punch 3| and a correspondingly secure positioning of the latter. By the aforesaid construction and coactionof the parts making up the punch structure, exact positioning of the punch proper 3| relative to the mechanism center line, as well as to the corresponding parts of the die, is secured, and a smooth cooperation between punch and die with the accuracy necessary to the manufacture of slide fasteners is attained.

The above described mounting and relation. of colt-like members to cutting punch is also useful in providing slight adjustment of the punch about the vertical center line of the die. Such adjustment may be made by the simple expedient of screwing up on one of the bolt-like members 36, 36a relative to the other, and is useful in correcting small deviations in punch positioning.

By further reference to Fig. 5, it will be observed that rearwardly of their heads 31, 31a, the bolt-like members are provided with vertically disposed flat surfaces 361), 360 which are adapted to bear {against the flat side faces of the punch member 36. Accordingly, tightening of theboltlike members functions to secure and properly position the punch member 36 against the vertical end wall 380 of the mounting block slot, with the flat surfaces 36?), 360 of the bolt-like members having side-gripping engagement with the sides of said punch member 36. Hence, the described punch holding means provides a common, yet simple, means for securing and properly positioning the two individual punch members 3| and 36.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. Punch and die mechanism for notching the longitudinal edges of strip material, comprising a punch and a die, of which the die consists of several operatively related die parts, means providing a slot in which said parts are disposed, and means including wedge-like surfaces operative between at least certain of said parts for holding said parts in exact symmetric position relative to the center line of the mechanism.

2. Punch and die mechanism for notching the longitudinal edges of strip material, including a. die having two semi-cylindrical die parts of identical cross section, means providing a slot into which said die parts protrude, and means for securing said die parts in fixed angular position with respect to each other and symmetrically to the sides of the die center line.

3. Punch and die mechanism for notching the longitudinal edges of strip material, including a die incorporating two part-cylindrical die parts of identical cross section, side blocks spaced to provide a slot and being each provided with a bore for receiving a die part, and means disposed in said slot and provided with inclined wedgelike surfaces against which the diametrical faces of said die parts engage, the construction and arrangement being such that said die parts are secured between the arcuate surfaces of the bore and said wedge-like surfaces and so that a corner of each part protrudes into the slot.

4. Punch and die mechanism for notching the longitudinal edges of strip material, including a. die consisting of side blocks spaced to provide a slot through which the strip is guided, a die part disposed in said slot and being provided with oppositely inclined wedge-like surfaces along an edge thereof which extends into the slot, the side blocks being provided with particular bores opening into the slot, die inserts of semi-circular section seated in said bores, with a corner of each extending into said slot, the diametrical faces of the inserts abutting against the wedge-like surfaces of said first die part, and means for securing said die inserts between said wedge-like surfaces and the arcuate walls of said part-cylindrical bores.

5. Punch and die mechanism for notching the longitudinal g s of str p material, including a vertically d ispbsed punch member having grooves of angular section in its side faces, and bolt-like members having heads provided with wedge surfaces, said heads extending into said grooves, and means for'tightening said bolt-like members in the direction of the center line of the punch and die mechanism.

RUDOLF FEI'IL.

REFERENCES CITED The following references are of record in the file of this patent:

Number Ekstedt Apr. 14, 1942 

